The BBC was found to have committed a "major breach" of broadcasting rules by not revealing that the presenter of a film about Gaza was the offspring of a Hamas representative, according to regulatory body Ofcom.
An probe by the broadcasting watchdog into the documentary titled Gaza: How to Survive a Warzone has concluded that the film was "substantially inaccurate".
The chief executive of the broadcaster had previously apologised, noting there had been "a significant failing in relation to truthfulness".
The regulator has instructed the BBC to air a prime-time statement about its findings.
"As this represents a major infringement of our rules, we are directing the broadcaster to air a announcement of our determinations against it on BBC2 at nine o'clock in the evening, with a schedule to be confirmed," the statement read.
'Risk to Undermine Credibility'
The watchdog's statement said: "The inquiry we conducted concluded that the programme's failure to disclose that the voice's male guardian occupied a post in the Hamas-run government was materially misleading.
"This implied that the public did not have vital facts which may have been very significant to their assessment of the voice and the content he provided.
"Trust is at the heart of the relationship between a media organization and its public, especially for a national broadcasting corporation such as the British Broadcasting Corporation.
"This failing had the possibility to undermine the exceptionally strong degrees of credibility that viewers would have put in a BBC factual programme about the Gaza conflict."
The programme was pulled from the online platform in last February after the presenter's personal associations came to light, and in the month of July an internal BBC review found it breached the broadcaster's journalistic standards on factual correctness.
A BBC spokesperson commented: "The authority's determination is in agreement with the results of Peter Johnston's review, that there was a major oversight in the programme in relation to the broadcaster's journalistic policies on accuracy, which reflects regulation 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we accept the regulator's ruling in full. We will follow the penalty as soon as the timing and language are finalised."
